Liquid fuel burner having plural whirl patterns of varying radii



Sept. 12, 1967 H. G. STALLKAMP 3,341,131

LIQUID FUEL BURNER HAVING PLURAL WHIRL PATTERNS OF VARYING RADII FiledJune 16, 1965 2 Sheets-Sheet l FIG.2

41 42 3K V f) 43 3a 33 37 "36 J4 INVENTOR Huben G. STaIIkamp ATTORNEYSept. 12, 1967 H. G. STALLKAMP 3,341,131

LIQUID FUEL BURNER HAVING PLURAL WHIRL PATTERNS OF VARYING RADII FiledJune 16, 1965 2 Sheets-Sheet 2 FIG. 3

capacity of such atomizers may thereby United States Patent 3,341,131LIQUID FUEL BURNER HAVING PLURAL WHIRL PATTERNS OF VARYING RADH HubertG. Stallkamp, Akron, Ohio, assignor to The Babcock & Wilcox Company, NewYork, N.Y., a corporation of New Jersey Filed June 16, 1965, Ser. No.464,334 4 Claims. (Cl. 239-402) The present invention relates to liquidfuel burners, and more particularly to fluid atomizing fuel burners forerosive liquid fuels.

In the successful combustion of a liquid fuel it is desirable to atomizethe fuel to a fine mist so that combustion air can be intimately mixedtherewith to complete the combustion process. Some liquid fuels, such asthe residual liquors resulting from a cellulosic pulping proc ess, areso erosive, as to reduce the atomizing eifect of one or more of theatomizer parts, necessitating frequent replacement of those parts.Residual liquors resulting from the sulphite cooking process areparticularly erosive due to dissolved and suspended solid matter thereinand also frequently contain fibrous material which tends to plug smalldiameter liquor flow passages in atomizer parts.

In accordance with the present invention I provide a liquid fuel burnerassembly constructed and arranged to successfully atomize erosiveliquids without excessive wear on the atomizer parts. This isaccomplished by a novel arrangement of atomizing fluid flow passagewaysarranged to intersect a high velocity flowing stream of the liquid to beatomized. The atomizing effect is accomplished out of direct contactwith the confining liquid flow passageway, which is relativelyunobstructed, to avoid excessive erosion of the atomizer parts andpluggage due to the presence of fibrous materials in the liquid.

The invention described herein is an improvement over the inventiondisclosed in US. Patent 2,812,212, issued Nov. 5, 1957, in the name ofRogers et al. In order to obtain higher capacities in fuel burners ofthe type described in the aforesaid patent without substantial increasein the pressure at which the liquid to be atomized is supplied, it islogical that the diameter of the fuel flow passageway be increased.However, it has been found that atomization of the fuel becomesincreasingly difficult as the fuel passageway diameter is increased dueto the inability to effectively penetrate and disrupt the central coreof the liquid fuel stream with atomizing fluid. Ac-

cordingly, it is an object of the present invention to provide amodified atomizer whereby more effective penetration and disruption ofthe fuel stream core isrealized so that atomization is improved and/orthe maximum =be effectively increased.

The various features of novelty which characterize my invention arepointed out with particularity in the claims annexed to and forming apart of this specification. For a better understanding of the invention,its operating advantages and specific objects attained by its use,reference should be had to the accompanying drawings and descriptivematter in which I have illustrated and described a preferred embodimentof my invention.

In the drawings:

FIG; 1 is an elevational view, partly in section, of a vapor generatingunit and furnace incorporating the burner of the present invention;

FIG. 2 is an enlarged sectional elevation of the liquid fuel burner;

FIG. 3 is a further enlarged longitudinal partial sectional view of theatomizer assembly of the liquid fuel burner;

FIG. 4 is a sectional view taken along line 44 of FIG.

, 3; and

2 FIG. 5 is a sectional view taken along line 5-5 of FIG. 3.

In the illustrated embodiment of the invention the burner is associatedwith a furnace 10 constructed and arranged for the combustion of a pulpresidual liquor resulting from the digestion of cellulosic material in arelatively pure magnesium base sulphite cooking liquor. The residualliquor from this process is particularly erosive to burner atomizerparts and the usual type of steam atomizing burner has had a useful lifemeasured in hours, and when constructed with expensive alloy parts alife not exceeding a few days at best. In this process the residualliquor is preferably 'burned in suspension. A high degree of sprayatomization of the liquor and thorough mixing with combustion air isdesirable to complete the combustion process and to cause the conversionof the magnesium sulfate in the liquor to a reactive form of magnesiumoxide.

Referring to FIG. 1 the furnace 10 is substantially completely linedwith high alumina refractory materials. High combustion temperatures areattained in this furnace. As shown, the rear wall 11 of the furnaceconsists of refractory blocks supported upon fluid cooled tubes 12 witha gas outlet 13 in the rear wall positioned upwardly adjacent thefurnace floor 14. The furnace floor is formed of hollow tile 15 coveredwith high aluminum refractories, with preheated air delivered to thefront portion of the floor through a valved duct 17, passed through thehollow tiles and discharged into the upflow open pass 18 of anassociated vapor generator 20.

Residual liquor at a concentration of 50 to 60% solids is delivered tothe upper portion of the furnace 10 through burner ports 16 positionedin opposite side walls of the furnace. The residual liquor is atomizedby the burners, as hereinafter described, mixed with air, and the com-vbustible matter therein burned in suspension within thefurnace 10.Leaving the furnace outlet 13 the combustion gases generated in thefurnace are passed through a series of fluid cooled upright open gaspasses 18, 21 and 22 and pass through the convection pass 23 of thevapor generator. The gases then pass through an air heater 24, and aresubsequently treated' in a supplementary system for the separation ofthe MgO solids in the gases and for the absorption of sulphur oxides ina wash liquid (not shown).

Advantageously the combustion air used in the furnace 10 is preheated toassist in an efficient and rapid combustion of the organic matter in theresidual liquor. Air from the forced draft fan 25 is passed through theair heater 24 into a duct 26 for distribution to the furnace 10 throughthe valved branch duct connections 17, 27 and 28. The duct connections28 extend upwardly on opposite sides of the furnace to open into ahorizontally disposed distributing manifold 30 which is provided with aseries of discharge pipes 31 extending between the tubes forming theroof of the gas passes 18 and 21 and arranged to discharge into the gasstream passing into the gas pass 21. The duct connections 27 likewiseextend from the duct 26 to an enclosed housing 33 surrounding the burnerports on the opposite sides of the furnace.

Each of the burner ports 16 is provided with an air register and aliquid fuel atomizer assembly, whereby the fuel and air are delivered tothe furnace 10 through each port. A vertical elevation (taken along thecenterline of a burner port and in a plane perpendicular to the sidewall of the furnace) of an individual air register and atomizer assemblyis shown in FIG. 2. A ring member 34 having an inwardly taperingsurface, and provided with a circumferentially arranged series of airdirecting 0 vanes 35, is fastened to the casing 36 enclosing therehousing 33 is spaced from and generally parallel to the casing 36, andis connected thereto by a series of brackets 38 arranged about theperiphery of the burner. A series of radially arranged air directingblades 40, each mounted on an individual axis, are interconected bylinkage for simultaneous adjustment from a common exterior lever 39. Theblades can be closed to substantially cut off air flow to the furnace,and can be adjustably opened to regulate the quantity of air passingtherethrough. Thus in all open positions, the air stream passing betweenadjacent blades 40 is given a swirling motion.

In addition, a slotted diffusion cone 41 is positioned in the burnerport 16 by the barrel 42 of the liquid fuel burner. The combination ofthe blades 40 and the diffusion cone 41 directs the flow of combustionair through the port in a whirling movement of the air mass surroundingand impinging upon a fine spray of liquor discharged from the atomizertip 43 of the burner. In the embodiment of FIG. 2, the barrel 42 isformed of an elongated tubular member projecting through a cover plate44 which is bolted to the plate 37. The barrel is centered so as to besubstantially coaxial with respect to the member 34, and is exteriorlyprovided with the conventional coupling provisions for the separateadmission of both liquid fuel and atomizing fluid, as indicatedgenerally at 45. The atomizing fluid may be steam, or other gaseous orvapor fluid.

Coaxially within the barrel 42 is the atomizer assembly, the tip 43 ofwhich is shown in detail in FIGS. 3, 4 and and includes inner and outertubes 46 and 47 respectively coaxially arranged to-define separate innerand outer passageways 48 and 50 for the respective flow of liquid fueland the atomizing fluid. A sprayer head 51 is threaded to the endportion of the tube 46 and is provided with a flanged end portion 52circumferentially engaging a shoulder 53 formed interiorly in the endportion of the tube 47. The head 51 serves to center and to maintain thedesired end spacing relationship between the tubes 46 and 47. A seriesof cir-cumferentially spaced ports 55 are drilled in the flanged endportion 52 to provide flow communication for the atomizing fluid betweenthe passageway 50 and an atomizing plate 56.

The atomizing plate 56 and a tip member 57 are assembled in coaxialabutting relationship to the head 51, and are maintained in position bya cap member 58 which is threaded onto the end of the outer tube 47. Aninwardly extending flange 60 of the cap member 58 engages acorrespondingly recessed outer portion of the tip 57 to maintain coaxialalignment of the assembly.

The upstream face of the atomizing plate 56, i.e., the face abutting theflanged portion 52 of head 51, is formed with an open-sided annulargroove or chamber 61 which is in communication with the ports 55 of theflanged end portion 52. Another open-sided annular groove 62 issimilarly formed in the opposite (downstream) face of the atomizingplate 56, i.e., the face abutting with the tip member 57. A series ofc-ircumferentially spaced openings 63 extend between the grooves 61 and62 to provide for the flow of atomizing fluid to the groove 62.

The atomizing plate 56 is formed with a central bore or throat 64 havinga diameter substantially equal to the diameter of the passage 48 so thatthe liquid flow path through the atomizer tip 43 -is substantiallyunobstructed. A plurality of circumferentially spaced fluid passages 62Aare formed in the downstream face of the plate 56, extending from thegroove 62 inwardly and through the confining wall of the throat 64. Thepassages 62A are arranged to discharge streams of atomizing fluid intothe throat 64 substantially tangentially thereto. Another set ofcircumferentially arranged fluid passages 61A are formed in the upstreamface of the atomizing plate 56 and extend from the groove 61 inwardly tothe throat 64, the passages 61A being arranged to discharge streams ofatomizing fluid into the throat 64 in directions more nearly radial thanthe passages 62A. Preferably, the passages 61A and 62A are arranged todirect their streams of fluid tangentially with respect to imaginarycircles of lesser diameter than the diameter of the throat 64. It shouldalso be noted that the discharge ends of the passages 61A and 62A arealternately spaced about the periphery of the throat 64 to effectmaximum disruption of the liquid stream.

In the embodiment shown, for ease of fabrication, the passages 61A and62A are rectangular in cross section; however, it will be understoodthat the cross-sectional shape can be varied within the scope of theinvention. Moreover, it should be understood that the number and size ofthe passages 61A and 62A can be varied within the scope of theinvention, depending on the pressure of the atomizing fluid and thedesired degree of atomization.

The tip member 57 is provided with an outwardly flaring conical surface66 diverging from the periphery of the throat 64 at an included angle ofapproximately 25- 30 to control the rate of expansion of the liquid fuelas it leaves the burner tip 43.

Operation In the operation of the atomizer, as the liquid fuel flowsfrom the passageway 48 into the throat 64 of the atomizing plate 56, itimpinges with streams of atomizing fluid discharged from the passages61A, the atomizing fluid being directed primarily to penetrate anddisrupt the central core of the fuel stream. Immediately thereafter andindependently thereof, the fuel stream is again impacted with atomizingfluid discharged from the passages 62A, which passages are arranged tosupplement the disrupting effect of the first atomizing fluid streamsand to impart a whirling motion to the fuel stream. The fuel stream,having thus encountered two successive and independent stages ofatomization arranged to disrupt the fuel stream and impart to it awhirling motion in progressive steps, is then subjected to controlledexpansion in the tip member 57 prior to discharge into the furnace.

While in accordance with the provisions of the statutes I haveillustrated and described herein a specific embodiment of the invention,those skilled in the art will understand that changes may be made in theform of the invention covered by the claims, and that certain featuresof the invention may sometimes be used to advantage without acorresponding use of the other features.

What is claimed is:

1. As an article of manufacture, a sprayer plate comprising a diskhaving an axial bore of substantially uniform diameter for passage of afibrous material-containing liquor therethr-ough, means forming a firstannular groove in one face of the sprayer plate radially spaced from andsurrounding said bore, means forming a plurality of firstcircumferentially spaced fluid flow passages disposed in a common planeand extending inwardly from said first annular groove to said bore, saidfirst passages being arranged to open into said bore in a directiontangential to a small diameter circle within said bore to act upon saidfibrous material-containing liquor, means forming a second annulargroove in the opposite face of the sprayer plate radially spaced fromand surrounding said bore, passage means interconnecting said first andsecond annular grooves, and means forming a plurality of secondcircumferentially spaced fluid flow passages disposed in a common planeparallel with and spaced from the plane of said first passages in theaxial direction of the bore and leading from said second annular grooveto said bore, said second passages being arranged to open into said borein directions more nearly tangential than said first passages anddirected to be tangent to a circle of greater diameter than said smalldiameter circle and less than the diameter of the bore.

2. A sprayer plate according to claim 1 wherein each of the said firstand second passages discharge into the said bore in the same directionof whirl.

3. A liquid fuel burner comprising walls defining coaxial passagewaysfor a fibrous material-containing liquor type of fuel and a highlyexpansible atomizing fluid respectively, a sprayer plate operativelyconnected to said passageways and having a central bore of substantiallyuniform diameter therethrough forming a continuation of the liquid fuelpassageway, means forming a first annular groove in one face of thesprayer plate radially spaced from and surrounding said bore and incommunication with said atomizing fluid passageway, means forming aplurality of first circumferentially spaced fluid flow passages disposedin a common plane and leading from said first annular groove to saidbore, said first passages being arranged to discharge streams of saidhighly expansible fluid into said bore substantially tangentiallythereto, means forming a second annular groove in the opposite face ofthe sprayer plate radially spaced from and surrounding said bore and incommunication with said atomizing fluid passageway, means forming aplurality of openings interconnecting said first and second annulargrooves, and means forming a plurality of second circumferentiallyspaced fluid flow passages disposed in a common plane spaced from theplane of said first passages in the axial direction of the bore andleading from said second annular groove to said bore, said secondpassages being arranged to discharge streams of said highly expansiblefluid into said bo-re to act upon said fibrous material-containingliquor in directions more near 1y radial than said first passages topenetrate and atomize the central core of the fuel flowing through saidbore.

4. A liquid fuel burner according to claim 3 wherein the first passagesopen into the bore at a location downstreamfuel flow-wise of thelocation where the second passages open into the bore.

References Cited UNITED STATES PATENTS 1,451,063 4/ 1923 Anthony239427.3 X 1,736,768 11/1929 Boynton 239405 X 1,789,977 1/ 1931 Hopkins239402 2,812,212 11/1957 Rogers et a1 239434 X 3,070,317 12/1962 Hunteret al. 239402 FOREIGN PATENTS 166,466 8/1950 Austria.

M. HENSON WOOD, JR., Primary Examiner.

VAN C. WILKS, Assistant Examiner.

1. AS AN ARTICLE OF MANUFACTURE, A SPRAYER PLATE COMPRISING A DISKHAVING AN AXIAL BORE OF SUBSTANTIALLY UNIFORM DIAMETER FOR PASSAGE OF AFIBROUS MATERIAL-CONTINING LIQUOR THERETHROUGH, MEANS FORMING A FIRSTANNULAR GROOVE IN ONE FACE OF THE SPRAYER PLATE RADIALLY SPACED FROM ANDSURROUNDING SAID BORE, MEANS FORMING A PLURALITY OF FIRSTCIRCUMFERENTIALLY SPACED FLUID FLOW PASSAGES DISPOSED IN A COMMON PLANEAND EXTENDING INWARDLY FROM SAID FIRST ANNULAR GROOVE TO SAID BORE, SAIFIRST PASSAGES BEING ARRANGED TO OPEN INTO SAID BORE IN A DIRECTIONTANGENTIAL TO A SMALL DIAMETER CIRCLE WITHIN SAID BORE TO ACT UPON SAIDFIBROUS MATERIAL-CONTAINING LIQUOR, MEANS FORMING A SECOND ANNULARGROOVE IN THE OPPOSITE FACE OF THE SPRAYER PLATE RADIALLY SPACED FROMAND SOURROUNDING SAID BORE, PASSAGE MEANS INTERCONNECTING SAID FIRST ANDSECOND ANNULAR GROOVES, AND MEANS FORMING A PLURALITY OF SECONDCIRCUMFERENTIALLY SPACED FLUID FLOW PASSAGES DISPOSED IN A COMMON PLANEPARALLEL WITH AND SPACED FROM THE PLANE OF SAID FIRST PASSAGES IN THEAXIAL DIRECTION OF THE BORE AND LEADING FROM SAID SECOND ANNULAR GROOVETO SAID BORE, SAID SECOND PASSAGES BEING ARRANGED TO OPEN INTO SAID BOREIN DIRECTIONS MORE NEARLY TANGENTIAL THAN SAID FIRST PASSAGES ANDDIRECTED TO BE TANGENT TO A CIRCLE OF GREATER DIAMETER THAN SAID SMALLDIAMETER CIRCLE AND LESS THAN THE DIAMETER OF THE BORE.